Pharmacologyis a discipline of medical sciences that also encompasses clinicalpharmacology. This science mainly deals with the effect of drugs andother pharmaceuticals on living organisms (Aref, 2015). Pharmacologyalso deals with the chemical properties of these drugs and theirdevelopment. One of the nurses’ primary responsibilities is theadministration of drug therapy. Drug administration is a process thathas some interrelated steps. It covers some medical professionals whounderstand how to manage diseases.
Therefore,it is necessary for them to have knowledge on the effects of drugs,patient’s response to the drugs and drug administration (Aref,2015). Understanding the intrinsic mechanisms of drugs, theirphysiological and biochemical properties is crucial. Knowledge of theroute of administration is vital since it affects the activeingredient’s bioavailability. As a principle of cure, it iscritical to understand pharmacology as a nurse. The purpose of thispaper is to look at a condition that affects the body systems, thepresenting signs and symptoms, the pathophysiology of the disease,and the drugs used to manage the condition. The condition covered inthis paper is glaucoma.
refers to some eye related disorders which cause harm or damage tothe optic nerve, which is crucial to good vision. If not managed intime, glaucoma leads to loss of vision and blindness (Facts about, 2017).
Increasedintraocular pressure is the major factor linked to optic nerve damage(Aref, 2015). This increase in pressure leads to the death of retinalganglion cells. An imbalance between the production and the drainageleads ocular hypertension.
Inopen-angle glaucoma, the aqueous humor drains at a lower speedthrough the meshwork drain. This low drainage rate leads to theaccumulation of the fluid inside the eye leading to an increase inthe pressure. The raised pressure causes mechanical strain and stresson the structures of the eye. The most affected parts are the laminacibrosa and the surrounding tissues. The strain and stress arisingfrom the mechanical stress leads to deformation, compression, andremodeling of the lamina cibrosa hence, disruption and damage ofaxonal transport (Aref, 2015). This disruption affects the deliveryof essential factors to the ganglion cells located in the retina thusleading to their damage.
Insome cases, optic nerve damage may occur to persons with intraocularpressures that fall within the normal ranges. In such cases, lowerlevels of the cerebrospinal fluid pressure in the subarachnoid spaceleads to a pressure ramp across the lamina. Other causes of glaucomainclude altered immunity, impaired microcirculation, oxidativestress, and excitotoxicity. Neurological pathological processes mayalso lead to secondary neurodegeneration of retinal cells and neuronsleading to glaucoma (Aref, 2015). Genetics contribute to the diseaseas some populations possess a higher risk of developing the diseasethan others.
Duringthe initial stages, open angle glaucoma presents with no symptoms.Usually, vision remains normal, and the disease can develop in one orboth eyes. Without proper intervention, people slowly lose theirperipheral vision. Other symptoms include blurred vision, severe headand eye pain, nausea and vomiting accompanied by severe eye pain.
Currently,some pharmacological agents are used to treat glaucoma. According tothe American Academy of Ophthalmology (2012), the main aim oftreating the disease is slowing down the disease progression andpreserving the quality of life. The decreased quality of life mayhave an early onset hence the need for early diagnosis and treatment.The best-proven method of treating glaucoma is by reducing theintraocular pressure. Examples of drugs used to treat glaucomainclude:
Thisgroup of drugs acts by antagonizing the enzyme carbonic anhydrase(Edward & Vajaranant, 2013). This enzyme is necessary for theproduction of the aqueous humor. In order to achieve optimum effect,more than 90% of the enzyme must be inhibited. By inhibiting theenzyme, the amount of the aqueous humor produced decreases therebylowering the intraocular pressure (Edward & Vajaranant, 2013).This class of drugs is classified further into systemic agents andtopical agents. An example of a CAI is acetazolamide.
Therapeuticdosage.0.25 to 1 gram daily in divided doses (BD-QID).
Preparationform and administration.Acetazolamide comes in the form of tablets or pills or intravenouspreparation.
Pharmacokineticproperties. Acetazolamidehas a protein binding of 70-90%, a biological half-life of 2-4 hoursand up to 90% of the drug`s excretion occurs through urine (Edward &Vajaranant, 2013).
Sideeffects. Theyinclude transient myopia, metabolic acidosis, paresthesia, weightloss, fatigue, malaise, potassium depletion, depression, nausea,vomiting, blood dyscrasia, and formation of renal calculi (Edward &Vajaranant, 2013).
Druginteractions.Acetazolamide may interact with digoxin, cisapride, furosemide, andanticonvulsants such as phenobarbital and primidone (Edward &Vajaranant, 2013).
Anexample of a beta blocker includes timolol. This group of drugs actsby blocking the sympathetic nerve endings found in the ciliaryepithelium. This blockade leads to a decrease in cyclic monophosphateproduction which, in turn, decreases the secretion of aqueous humorby about 20-30% (Edward & Vajaranant, 2013).
Therapeuticdosage. Eyedrops instilled into the affected eyes twice to four times a daydepending on the concentration of the drug.
Preparationform and administration.Comes in the form of eye drops with a concentration of either 0.25%or 0.5%
Pharmacokineticproperties.Nearly 90% of the drug is absorbed. It has a half-life of four hours.Timolol is metabolized in the liver and excreted in urine. Less than10% is bound to plasma proteins.
Sideeffects.Ocular side effects include corneal anesthesia, punctate keratitis,and allergic reactions. Systemic effects include bradycardia,syncope, depression, decreased libido, and mood swings (Edward &Vajaranant, 2013).
Druginteractions.Interactions may occur with catecholamine-depleting agents, NSAIDs,calcium antagonists, clonidine, quinidine, diltiazem, and digitalis(Edward & Vajaranant, 2013).
Itis vital to discuss all your drugs with your pharmacist before usingacetazolamide. All over the counter medications, dietary supplements,recreational drugs and vitamins have to be taken after the input ofthe pharmacist or doctor. Avoid alcohol during this period. Avoideating grapefruits or its juice while taking acetazolamide.Grapefruits slow the breakdown of acetazolamide which may lead topotentially dangerous drug levels in the blood (Edward &Vajaranant, 2013).
Itis vital to discuss all your drugs with your pharmacist before usingtimolol (Edward & Vajaranant, 2013). All over the countermedications, dietary supplements, recreational drugs and vitaminshave to be taken after the input of the pharmacist or doctor. Avoidalcohol intake as it may worsen some of the side effects of thisdrug.
Nursingpriorities in managing glaucoma
Duringthe treatment period, nurses should prevent further visualdeterioration, provide information about the disease and itsmanagement, prevent complications, and help the patients to adapt todecreased visual acuity.
is among the leading causes of blindness. Early detection, diagnosis,and treatment can assist in preventing vision loss due to thedisease. If a person presents with symptoms similar to those ofglaucoma, the primary care nurse should refer that patient for a fullophthalmologic examination to rule out the disease. In future, moreresearch should be carried out on a molecular level, especiallygenome-wide studies so that the DNA fragment variations associatedwith the disease can be cross-checked to come up with a possiblepathway of tackling the disease.
Aref,A. A. (2015). Essentialsin Ophthalmology: Advanced Surgery.Cham, SWITZERLAND: Springer International Publishing.
Edward,D. P., & Vajaranant, T. S. (2013). .Oxford: Oxford University Press.
FactsAbout . (n.d.). Retrieved January 16, 2017, fromhttps://nei.nih.gov/health/glaucoma/glaucoma_facts
.(2012). San Francisco, CA: American Academy of Ophthalmology.